1. Field of the Invention
The invention relates in general to a three-dimensional (3D) image processing technique, and more particularly, to a technique for adjusting a distance and a viewing angle relative to a 3D image and an observer of the 3D image.
2. Description of the Related Art
With advancements in related software and hardware techniques, commercial and household 3D display equipment has gradually matured, and 3D image techniques have also drawn much attention in the multimedia field. Current 3D display techniques are in general divided into an active type and a passive type.
An active 3D image display technique refers to alternately presenting left-eye and right-eye images on a monitor. Dedicated glasses worn by a viewer shield the right eye of the viewer when a left-eye image is presented and shield the left eye of the viewer when a right-eye image is presented. The visual system of the viewer automatically combines the left-eye image and the right eye image to form a 3D image. Due to vision persistence, the brief shieldings by the 3D glasses against the presented images remain unnoticed to the viewer as long as a switching frequency of the left-eye and right-eye images is fast enough.
A passive 3D image display technique refers to simultaneously presenting left-eye and right-eye images in a same image frame. Referring to FIG. 1, odd-row pixels R1, R2, R3 . . . correspond to the right-eye image, and even-row pixels L1, L2, L3 . . . correspond to the left-eye image, with the two being horizontally staggered. A passive 3D image display comprises an exteriorly adhered polarizing film. For example, a polarization angle corresponding to the odd-row pixels R1, R2, R3 . . . may be designed as 45 degrees, and polarization angle corresponding to the even-row pixels L1, L2, L3 may be designed as 135 degrees. Thus, the left lens and the right lens of the glasses worn by the viewer respectively allow the passing of light beams with a polarization angle of 45 degrees and 135 degrees, so that different images can be received by the left and right eyes, respectively. Similarly, the viewer automatically combines the left-eye image and the right eye image received at the same time through human visual characteristics to form a corresponding 3D image.
For both of the active and passive 3D image display techniques, the completed left-eye images and right-images can only be modified or adjusted with complex and expensive devices. However, a trend to provide a user with user-independent options and flexibilities for adjusting image content emerges, such as allowing a user to manually adjust brightness, contrast and depth of 3D images.